Romney, who has battered Gingrich in a flood of television ads and two debates in Florida during the last week, opened a double-digit advantage over the former House of Representatives speaker in three polls released today.

Gingrich said the race was closer in Florida than the polls indicated and vowed to fight on beyond Tuesday’s vote. Conservatives eventually would rally behind his candidacy and block Romney’s nomination, he said.

“I believe the Republican Party will not nominate a pro-abortion, pro-gun control, pro-tax increase moderate from Massachusetts,” Gingrich said after attending a Baptist mega-church on Sunday in Lutz, Florida.

“They will not nominate somebody who raises millions from Wall Street to run ads that are false,” he said. “So this is going to be a straight out contest for the next four or five months.”

Earlier, in appearances on two morning talk shows, Gingrich accused Romney of distorting his record.

“He has a basic policy of carpet-bombing his opponent,” he said on Fox News Sunday. “I give Governor Romney’s campaign due respect for the sheer volume of negativity that they use and the sheer amount of money they raise on Wall Street.”

Romney told supporters in Naples, Florida, that Gingrich was making excuses and should take a look in the mirror.

“My own view is that the reason Speaker Gingrich has been having a hard time in Florida is the people of Florida have watched the debates and listened to the speaker, have listened to the other candidates and have said, ‘You know what? Mitt Romney’s the guy we’re gonna support’,” he said.

Gingrich picked up the endorsement on Saturday night of former rival Herman Cain, who dropped out of the Republican race in December after allegations of sexual harassment and an extramarital affair.

But polls have shown the race moving toward Romney in Florida for days, reversing the momentum that Gingrich built after scoring a double-digit upset of Romney in South Carolina on January 21.

A Miami Herald poll on Sunday gave Romney, the former Massachusetts governor, an 11-point advantage in Florida on Gingrich. An American Research Group poll also put the margin at 11 points, while an NBC News/Marist College poll had Romney ahead by 15 points.

‘IN THE DRIVER’S SEAT’

“Mitt Romney has shored up support among his key backers while cutting his losses among Tea Party voters,” Marist pollster Lee Miringoff said. “The net effect is that he is in the driver’s seat as Tuesday’s primary approaches.”

Gingrich acknowledged he faced an “uphill” battle to overtake Romney in Florida but disputed the size of Romney’s lead.

“I think it will be much, much closer than these polls, we have a shot at winning,” Gingrich said on Fox. “But frankly it’s uphill against the sheer weight of Romney’s money and the negativity of his campaign.”

A win in Florida would be a vital boost for Romney, who was backed in the last week by several prominent conservatives and party leaders worried a Gingrich nomination would doom Republicans in the November 6 election against President Barack Obama.

Gingrich said he wanted to ruffle feathers in the party establishment and he was not bothered by criticism from party elders like former Senate Republican leader Robert Dole.

“This campaign is precisely about challenging the establishment, and I think Senator Dole is a quintessential part of the establishment,” he said. “I’m willing frankly to have a lot more challenges to the old order than he would be comfortable with.”

Gingrich said he and rival Rick Santorum were splitting the conservative vote and he could beat Romney once conservatives rally around his bid. Santorum, a former U.S. senator from Pennsylvania, has rejected suggestions that he drop out of the race.

“This race is going to go on. The conservatives clearly are rejecting Romney. He is nowhere near getting a majority,” Gingrich said on ABC’s This Week.

“My hope is that gradually conservatives will come together and decide that a Newt Gingrich conservatism is dramatically better than Mitt Romney’s liberalism,” he said.

Florida is the fourth contest of the Republican race and the biggest of the states to vote so far. Santorum won Iowa, while Romney won New Hampshire before Gingrich took South Carolina.

Some Republicans in Florida said they were worried about the negative tone of the contest and whether it would hurt the party in the general election campaign against Obama.

“I’m very concerned about the way the Republicans are beating the hell out of each other,” said Chuck Aserno, a Miami resident who is backing Romney. “I think all they’re doing is making it more difficult for whoever wins this to win against President Obama.”

Representative Paul Ryan, the chairman of the House Budget Committee, said he was dismayed by attacks during the campaign on Romney’s work at a private equity firm that critics said plundered companies and cut jobs.

“We need to defend the morality of a system in America that you’re free to take risks, to make money to create jobs – and to do it however you want to as long as it’s legal. That’s something we should be proud of,” Ryan said on Fox.